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Instabilités des membranes lipidiques inhomogènes. Implications biologiques.

Abstract : Lipid vesicles are a paradign for the study of mechanical and physicochemical properties of cellular membranes. They have been widely studied for about thirty years and, in the case of double-layered homogeneous vesicles, their properties are well understood. It is now possible to create vesicles with a mixture of lipids. In such systems, phase separation can occur leading to the formation of domains of different composition. Similar structures of small size, called ' rafts', can exist in the cellular membranes. Various experiments on multiphasic vesicles show that this inhomogeneity tends to destabilize the shape. We have modelled three different instabilities observed in experiments to gain insight on the mechanical properties of the vesicles and how they are affected by phase doamins. Two of these instabilities are associated with deformations out of the bilayer plane: the rupture of a tube of membrane, caused by internal mechanical constraints, and the ejection of a domain of a stretched vesicle, either by the absorption of molecules or by a change of the osmotic pressure. Finally, we have modelled the hydrodynamic behavior of the bilayer and introduce a concept of viscosity associated with its two-dimensional character.
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Contributor : Jean-Marc Allain <>
Submitted on : Tuesday, January 10, 2006 - 9:58:05 AM
Last modification on : Thursday, December 10, 2020 - 12:38:10 PM
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  • HAL Id : tel-00011333, version 1


Jean-Marc Allain. Instabilités des membranes lipidiques inhomogènes. Implications biologiques.. Biophysique []. Université Paris-Diderot - Paris VII, 2005. Français. ⟨tel-00011333⟩



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